Capacitive Syringe Content Sensing with Shielded Electrodes
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Solution Overview
Problem
Current drug delivery systems rely on indirect mechanical measurements for monitoring drug delivery, which are prone to mechanical failures and inaccuracies due to manufacturing issues and environmental interference.
Innovation Solution
A capacitive sensor system using a pair of electrodes and shielding to directly measure drug content within a syringe by varying capacitance based on dielectric properties, with electrode shields to mitigate external interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual monitoring methods are used, then device complexity is reduced, but measurement precision and reliability of drug delivery monitoring deteriorate
Solution Approach 1:
The monitoring system embeds multiple functional components within each other: the sensor is integrated into the drug delivery device, the processor is contained within the monitoring system, and the communication module is nested within the processor architecture. This nesting approach enables precise monitoring while maintaining a compact, manageable system structure that doesn't excessively increase complexity.
Solution Approach 2:
The monitoring system is designed to work with multiple types of drug delivery devices (infusion pumps, insulin pens, inhalers) through universal communication protocols and standardized sensor interfaces. This multi-functionality allows a single monitoring system to provide accurate measurements across different device types without requiring device-specific customization, thereby improving measurement precision without proportionally increasing system complexity.
2Measurement precision
If frequent monitoring is implemented, then measurement precision improves, but use of energy increases
Solution Approach 1:
The monitoring system implements periodic sampling of drug delivery data at optimized intervals rather than continuous monitoring. The processor analyzes delivery patterns and adjusts sampling frequency dynamically - increasing monitoring during critical delivery phases and reducing frequency during stable periods. This periodic action maintains measurement precision for critical events while significantly reducing overall energy consumption compared to continuous monitoring.
Solution Approach 2:
The system includes automatic low-power modes where the sensor and processor enter sleep states between monitoring cycles. The communication module autonomously buffers data and transmits only when necessary, and the system self-adjusts monitoring frequency based on battery status and delivery phase. This self-service approach allows frequent monitoring capability while managing energy consumption through automated power management.
3Reliability
If real-time communication is enabled, then reliability of drug delivery monitoring improves, but use of energy by stationary object increases
Solution Approach 1:
The communication module operates in periodic bursts rather than continuous transmission. It collects data locally during monitoring cycles and transmits aggregated information at scheduled intervals or when significant events occur. This periodic communication maintains reliability by ensuring critical data is transmitted while dramatically reducing energy consumption compared to continuous real-time communication.
Solution Approach 2:
The system implements feedback mechanisms where the receiver acknowledges data receipt and requests additional information only when necessary. The transmitter adjusts its communication frequency and data volume based on feedback about data completeness and receiver status. This feedback-driven approach ensures reliable monitoring information is transmitted while minimizing unnecessary energy expenditure on redundant communications.
Data Source
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AI summary
A sensor for measuring the contents of a syringe or other container is described. The sensor includes a voltage source, a pair of electrodes, a measurement circuit, and an electrode shield. The voltage source is coupled to the electrodes, and the electrodes apply an electric field through at least a portion of the container or syringe. The measurement circuit measures capacitance across the electrodes. The electrode shield partially encloses the pair of electrodes. The electrode shield may include an inner electrode shield having a second voltage, and an outer electrode shield having a third voltage.